I don't know what to call the stereo sound. See some reviews below.
" The musical numbers were recorded in multi-directional mono, placing microphones around different parts of the orchestra. Those were all mixed down to mono at the time the film was released. The parts of those recordings were...
I remember a long time ago, when the DVD of Sun Valley Serenade came out, a reviewer was shocked to hear stereo sound when the songs played. They thought it was maybe reprocessed mono to stereo but, later found out that stereo tracks were found. Am I thinking of the right movie title?